The Wifi wireless is the standard 802.11 a/b/g/n versions. 3G is the cellular data network using the GSM(2G) and USDPA(3G) signals. iPad should support the 5GHz networks since their other Wifi products do. Speeds are 7.2 Mbit/sec. AT&T speeds are 3.6 Mbit/sec, just like your iPhone. iPad supports the micro-SIM card, the iPhone has a regular SIM card.

The iPad is not locked so if your favorite carrier supports GSM(2G) or USDPA(3G) you should be good. replace the Micro-SIM on the iPad and you are rocking. The 3G version of the iPad comes with a micro-SIM eject tool.

Pricing with AT&T are: 250MB of data is $14.99 per month or Unlimited data is $29.99 per month. You can change plans at any time, add another 250MB chunk at any time, cancel or sign up and any time. iPad monitors your data usage and will remind you if you are getting close to the end of your data allotment.